Classifications

• • G—PHYSICS
  • G04—HOROLOGY
  • G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
  • G04B17/00—Mechanisms for stabilising frequency
  • G04B17/04—Oscillators acting by spring tension
  • G04B17/06—Oscillators with hairsprings, e.g. balance
• • G—PHYSICS
  • G04—HOROLOGY
  • G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
  • G04B15/00—Escapements
  • G04B15/06—Free escapements
• • G—PHYSICS
  • G04—HOROLOGY
  • G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
  • G04B17/00—Mechanisms for stabilising frequency
  • G04B17/04—Oscillators acting by spring tension
• • G—PHYSICS
  • G04—HOROLOGY
  • G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
  • G04B29/00—Frameworks
  • G04B29/02—Plates; Bridges; Cocks
  • G04B29/022—Bridges
• • G—PHYSICS
  • G04—HOROLOGY
  • G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
  • G04B29/00—Frameworks
  • G04B29/02—Plates; Bridges; Cocks
  • G04B29/027—Materials and manufacturing
• • G—PHYSICS
  • G04—HOROLOGY
  • G04D—APPARATUS OR TOOLS SPECIALLY DESIGNED FOR MAKING OR MAINTAINING CLOCKS OR WATCHES
  • G04D3/00—Watchmakers' or watch-repairers' machines or tools for working materials
  • G04D3/0069—Watchmakers' or watch-repairers' machines or tools for working materials for working with non-mechanical means, e.g. chemical, electrochemical, metallising, vapourising; with electron beams, laser beams
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B81—MICROSTRUCTURAL TECHNOLOGY
  • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
  • B81B3/00—Devices comprising flexible or deformable elements, e.g. comprising elastic tongues or membranes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B81—MICROSTRUCTURAL TECHNOLOGY
  • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
  • B81B5/00—Devices comprising elements which are movable in relation to each other, e.g. comprising slidable or rotatable elements
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B81—MICROSTRUCTURAL TECHNOLOGY
  • B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
  • B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
  • B81C1/00015—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems
  • B81C1/00134—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems comprising flexible or deformable structures
  • B81C1/00142—Bridges

Definitions

• the present invention relates to the field of watchmaking. More particularly, it relates to a multi-level micromechanical timepiece comprising movable elements relative to each other and having a monolithic structure.
• the invention finds particular application in the production of oscillators and regulator components for the watch industry.
• the invention also relates to a method of manufacturing such a multi-level micromechanical timepiece.
• Watchmaking mechanisms require the production and implementation of a very large number of parts of various sizes, shapes and sections, arranged in relation to each other within the mechanisms to fulfill the different particular functions. assigned to these mechanisms, be it the counting and display of time calendars or other ancillary functions.
• the isochronism and the power reserve among others the various components of such mechanisms generally have little evolved in their forms but have however considerably evolved in their constituent materials, their manufacturing processes, their mechanical and physical properties and, consequently, their pure performances and those of mechanisms implementing them.
• the present invention thus aims to at least partially solve the defects of watch components formed from semiconductor materials for the realization of timepieces and clockwork mechanisms more robust and compact, and having fewer separate components. Disclosure of the invention
• the invention relates to a micromechanical timepiece, comprising a plurality of functional subassemblies integral and superimposed on each other in a direction to form a multi-level assembly, characterized in that each functional subassembly consists of the same semiconductor material and is secured to another subassembly by bridges made of said semiconductor material, and in that at least one said subassembly comprises at least one at least two distinct portions, said portions being movable relative to one another and with respect to another subassembly of which at least one said portion is integral, via at least one deformable connection formed of material between said portions.
• said subsets, their portions, bridges and deformable link (s) form a monolithic piece.
• said subsets and bridges are made of silicon (Si), silicon-germanium alloy (Si x Gei -x), germanium (Ge), gallium nitride (GaN), or silicon carbide (SiC).
• said subsets and bridges consist of polycrystalline or amorphous silicon.
• said subsets and bridges or parts thereof are made of doped silicon, in particular to make it conductive and / or to improve its thermocompensation properties.
• said subassemblies and bridges or parts thereof can further be coated with a functionalization layer, in particular a thermocompensation layer, based on silicon dioxide (SiO 2) for example, a damping layer or a protective layer.
• a functionalization layer in particular a thermocompensation layer, based on silicon dioxide (SiO 2) for example, a damping layer or a protective layer.
• SiO 2 silicon dioxide
• a protective layer polymeric materials such as parylene or a monolayer of silanes provide advantageous performance.
• said subsets are spaced from each other by a distance of between 0.1 and 20 microns, preferably between 0.5 and 10 microns, by bridges in the (Z) direction.
• the deformable links consist of flexible blades whose thickness, measured in a plane perpendicular to the direction (Z) is between 2 and 50 microns.
• said portions of a said subassembly are rotatable about a virtual axis of rotation or in translation in a plane perpendicular to the direction (Z).
• At least two said subsets directly superimposed in the direction (Z) form a trundle structure, that is to say composed of integral members of said subsets and nested within each other. other with play, in particular to provide a device for limiting movement (stop, shock prevention) and / or guiding and / or to provide a self-alignment in the direction (Z) between two subsets.
• the trundle structure may comprise interdigitated members, that is to say members with fingers, extending from a base in opposite directions in directions parallel to the direction (Z), for example to limit the lateral stroke perpendicular to the direction (Z) of said subsets relative to each other.
• the present invention also relates to a method of manufacturing a timepiece as previously defined.
• this method essentially comprises the following successive steps: a. Providing a substrate of a semiconductor material, said substrate preferably comprising alignment markings on a first face, b. Deposit on a second face of the substrate a layer of sacrificial material of height h determined and homogeneous over the entire surface of the second face of the substrate; vs. Structuring the layer of sacrificial material by an etching process to form openings therein throughout its height h; d.
• a growth layer of a semiconductor material of the same nature as the substrate on the layer of sacrificial material of in order to fill the previously formed openings and completely cover it e. Structuring the growth layer by a deep etching process to form a first functional subset comprising movable portions relative to one another and to the substrate through at least one deformable link; f. Structuring the semiconductor material substrate by a deep etching method forming a second functional subset comprising portions movable relative to each other and with respect to the growth layer via a deformable link at least ; boy Wut. Remove the layer of sacrificial material between the substrate and the growth layer to form connecting bridges between said subsets and release said timepiece.
• steps e) and f) involve the implementation of a reactive ion etching process
• the substrate and the growth layer are formed of the same semiconductor material, including silicon (Si), silicon-germanium alloy (Si x Gei -x), germanium (Ge), of nitride gallium (GaN), or silicon carbide (SiC)
• the substrate and the growth layer are formed of the same doped semiconductor material.
• the growth layer is formed by growth of silicon on the substrate in the openings formed in the sacrificial material layer and on its surface which, in the case of silicon as a growth layer, could advantageously be SiO 2.
• steps b) to e) n times are repeated, n being an integer between 1 and 5, before or after step f).
• steps b) to e) n are repeated, n being an integer between 1 and 5, on both sides of the substrate.
• an intermediate step of planarization of each growth layer is carried out between steps d) and e), in particular by polishing.
• FIG. 1 represents a section in a vertical plane of a timepiece according to the invention
• FIGS. 2 and 3 show two embodiments of a timepiece according to the invention
• FIG. 4 represents the steps of the method of manufacturing the timepiece of FIG. 1;
• FIG. 5 represents a variant of the method of manufacturing a timepiece of FIG. 4.
• the present invention proposes a new type of watch components of multi-level structure, that is to say comprising a plurality of functional "stages" integral with each other, said so-called functional stages integrating movable elements with respect to the others. floors.
• watchmaking components include in particular flip-flops or jumpers, again mainly oscillators for regulating members.
• FIG. 1 represents, in section along a vertical plane XZ, defined in an orthonormal frame ⁇ , ⁇ , Z, a first exemplary embodiment of a timepiece 1 according to the present invention as defined in the claims.
• the timepiece 1 of the invention forms a clock component of monolithic structure obtained by methods of etching a single semiconductor material as will be described below with reference to FIGS. 3 to 6.
• Timepiece 1 comprises in the example shown two functional subsets 1 a, 1 b integral with each other and superimposed on each other in the direction Z by bridges 5 formed of material between the sub-assemblies 1a, 1b to form a multi-level component in this direction at least.
• Each functional subset 1 a, 1 b and the bridges 5 thus consist of the same semiconductor material and the subsets 1 a, 1 b are spaced from each other by a distance of between 0.1 and 20 microns, preferably between 0.5 and 10 microns, by the bridges 5 in the Z direction.
• at least one of the subsets 1 a, 1 b is composed of at least two distinct portions 2, 3 of which 1, in the figures the portion 3, is movable through at least one deformable connection (not shown in the figures) relative to the other portion, in the figures the portion 2, which is integral with at least one said portion 2, 3 of the other subset 1a, 1b.
• the deformable connection is advantageously formed of material between said portions 2, 3 during the etching of the timepiece, in particular takes the form of one or more flexible blade (s) whose thickness, measured in a plane perpendicular to the Z direction is between 2 and 50 microns preferably.
• the subsets 1 a, 1 b are offset and separated by a space 4 in the direction Z from each other so that the movable portions 3 of each subassembly 1 a, 1 b can move without friction in planes parallel to the XY plane, perpendicular to the Z direction.
• FIG. 2 thus represents a timepiece 1 according to the invention in which cavities 7 are arranged and in which the mobile portions 3 of a said subset 1b are able to move.
• Such an embodiment thus has the advantage of providing a micromechanism, in this case the subset 1b at least, integrated, or encapsulated, between two levels, here constituted by subsets lower 1a and higher 1 c .
• the timepiece 1 thus formed is extremely robust and protected from exogenous disturbances such as dust or the like that could be inserted otherwise between the portions 2, 3 of the part and its subassemblies 1 a, 1 b.
• FIG. 3 represents another variant embodiment in which the timepiece 1 comprises a cavity 7 formed between two sets 1a, 1b superimposed in the Z direction and form a nesting structure composed of nested members 8, 9 in each other with play in the direction Z, one of said members 8, 9 at least also being a movable portion 2, 3 of a subset 1a, 1b.
• These nested members 8, 9 advantageously make it possible to produce a stop structure internal to the timepiece 1, thus making it possible to limit the displacements and to absorb the shocks of the mobile portions 2, 3 in planes perpendicular to the Z axis. or even to provide a movement guide according to the particular configuration of said members 8, 9.
• the latter may in particular take the form of fingers or combs extending from a subassembly 1a, 1b to the other subassembly in opposite directions and without contact with them. They can also take any other form adapted to the needs, provided that said members can nest into each other along the axis Z.
• the semiconductor material constituting the piece timepiece 1 and all its functional elements is polycrystalline silicon.
• amorphous silicon may also be used, as well as other commonly employed semiconductor material in the fields of microelectronics such as silicon-germanium alloy (Si x Gei -x), germanium (Ge), gallium nitride (GaN), or silicon carbide (SiC).
• the timepiece 1 of the invention makes it possible for the first time to design and manufacture micromechanical watchmaking components, and especially oscillators, equipped with a stepped monolithic structure and integrating mobile portions 3 via deformable links. realized in the mass of the timepiece 1 and the different subsets 1a, 1b forming the levels or stages thereof.
• Such a monolithic structure of the timepiece 1 of the invention provides an optimal structural alignment of the different subsets 1a, 1b along the Z axis of superposition of said subsets 1a, 1b, which corresponds to this will emerge subsequently to the growth axis of the constituent material of the timepiece.
• the intrinsic mechanical strength of the timepiece 1 of the invention and its various subsets 1a, 1b and portions 2, 3 is thus greatly improved, as well as the accuracy of the mobility games between moving portions, and therefore the accuracy and reliability of the timepiece 1 with respect to the analogous watch components obtained by assembling the various subassemblies, in particular by technical bonding or surface hybridization complexes from components derived from silicon wafers. on insulator (or SOI for silicon on insulator in English).
• the timepiece of the invention being formed of a single material without assembly thereof also has a thermal expansion coefficient (CTE) homogeneous throughout the room, allowing greater stability and response thermal thereof, so a better isochronism potential of a regulating member incorporating such a timepiece.
• CTE thermal expansion coefficient
• thermal coefficient of expansion is also possible by favoring as material constituting the timepiece the use of a doped silicon, in particular an n-type doping. Such doping can furthermore provide, if necessary, a conductive character to the silicon forming the part of time of the invention. It is also possible to optimize the overall coefficient of thermal expansion of the timepiece of the invention by treating subsets 1a, 1b and bridges 5 or parts of them with a layer of functionalization such as a thermocompensation layer, for example silicon oxide in the case of a silicon micromechanism.
• a layer of functionalization such as a thermocompensation layer, for example silicon oxide in the case of a silicon micromechanism.
• a functionalization layer on the subsets 1a, 1b and bridges 5 or parts thereof is not limited, of course, not only to the adjustment of the thermal properties of the timepiece 1 of the invention but may also be useful for any other functional improvement of the inherent properties of the constituent material of the timepiece 1 or its performance over time. It is thus possible in particular to envisage a coating of the subsets 1a, 1b and mobile portions 3 thereof by a damping layer or a protective layer such as a corrosion prevention layer, a layer of material hydrophobic, a chemical barrier layer or a tribological layer.
• Timepiece 1 of the present invention in its general form shown in FIG.
• a first silicon substrate S is provided on a first face S 1 with alignment markings 6 adapted to position the substrate on a support in a reference position. from which the substrate will be structured in successive steps.
• a layer 10 of sacrificial material for example preferably silicon dioxide, is then deposited on a second face S2 opposed to the first of the substrate over the entire surface of the second face S2 of the substrate S .
• a third step (c) shown in Figure 2B structure the sacrificial material layer 10 by a deep etching process to form therein openings 1 1 over its entire height.
• the engraving process may be of various nature but reactive ion etching processes, better known by the acronym RIE for "Reactive Ion Etching" in English, are preferred.
• the sacrificial layer thus structured is then deposited thereon a silicon growth layer 20 in a fourth step (d).
• steps b) and / or d) it will be possible after steps b) and / or d) to provide an intermediate step for flattening the surface of said layer of sacrificial material 10 and growth layer 20, in particular by polishing or grinding.
• Such a planarization step makes it possible to guarantee a perfectly flat surface state for the growth of the growth layer 20 and / or any other additional layer.
• the following two steps consist in structuring the growth layer 20 on the one hand (FIG 4D) and the substrate S on the other hand (FIG 4E), again by a method of deep etching of type DRIE (Deep Reactive Ion Etching in English), to form openings 12 defining said portions 2, 3 of a first and a second subassembly 1a, 1b, a portion 3 being movable relative to the other via at least one deformable link.
• the formation of the portions 2, 3 then results entirely from the mask defining the particular configuration chosen by design by the designer or designers for the timepiece 1.
• the layer of sacrificial material 10 must be withdrawn between the substrate S and the growth layer 20 previously structured so as to form the connecting bridges 5 between said subassemblies 1. a, 1b, and if necessary that intermediate links (not shown in Figure 4) between the individual pieces thus formed.
• the said clockwork part (s) 1 thus formed in the substrate S is released, if necessary by breaking the intermediate links using any suitable tool.
• the method of the invention does not involve any machining and the formation of subsets 1a, 1b of the timepiece of the invention results essentially from growth techniques, method photolithography and etching which ensures an optimal alignment of the subsets 1a, 1b and their movable elements 3,4 depending on the desired design, without the application of external mechanical stresses in the constituent material of the room .
• the implementation of a structuring of the substrate S, the sacrificial material layer 10 and the growth layer 20 by etching processes also allows a very good dimensional control of the formed parts and their functional elements, in particular deformable links between the portions 2, 3, as well as their geometry, and despite their very small dimensions of a few tenths of millimeters to a few millimeters barely. This ensures a better reproducibility of manufacture as well as a better intrinsic and extrinsic quality of the timepieces 1 thus produced.
• the removal of the sacrificial layer 10 of silicon dioxide, in the case of the use of silicon as a structural material, before release of the timepieces 1 can be carried out in a conventional manner by etching on the basis of hydrofluoric acid. liquid or gaseous phase for example.
• the substrate S and the growth layer 20 used in the process of the invention consist of the same semiconducting material, preferably of silicon, polycrystalline or amorphous material. if necessary doped.
• Other semiconductor materials are also envisaged, in particular silicon-germanium alloy (Si x Gei -x), Germanium (Ge), gallium nitride (GaN) or silicon carbide (SiC) as previously described.
• FIGS. 5A to 5G show a variation of the manufacturing method previously described and shown in FIG. 4, and more particularly of step d) of structuring the growth layer 20 to obtain a timepiece 1 as represented in FIG. 2, comprising one or more cavities 7.
• FIG. 5A represents the intermediate state of a timepiece according to the invention at the end of step d) of structuring the growth layer.
• a new step of depositing a second layer 100 of sacrificial material is carried out here as represented in FIG. 5B. therefore S1O2.
• This second layer 100 then fills the openings 12 previously structured by etching in the growth layer 20.
• FIG. 5C a new structuring of the second layer 100 of sacrificial material is carried out, identical to step c) of the method of FIG. 4, to form openings 10, which are then filled as shown in FIG. 5D by a second silicon growth layer 200.
• the first and the second layer 10, 100 of sacrificial material form between the substrate S, the first growth layer 20 and the second layer of growth 200 a dissolvable sacrificial nucleus that can then dissolve to release the cavities 7 and form the timepiece 1 of Figure 2.
• fine injection channels 30 are pierced in the second growth layer 200, into which a solution for dissolving the layers 10 and 100 of sacrificial materials, which are evacuated, is then injected. by the same channels 30, to release the cavities 7.
• the present invention thus provides a new type of micromechanical watch components and timepieces of multi-level structure and incorporating mobile functional elements by flexible deformable links of the flexible blade type and their manufacturing processes.

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• Optics & Photonics (AREA)
• Plasma & Fusion (AREA)
• Micromachines (AREA)

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• 2017
  • 2017-02-22 CH CH00205/17A patent/CH711828A2/fr unknown
• 2018
  • 2018-02-07 US US16/486,747 patent/US11809136B2/en active Active
  • 2018-02-07 EP EP18709929.6A patent/EP3586200A2/de active Pending
  • 2018-02-07 WO PCT/EP2018/052999 patent/WO2018153664A2/fr unknown
• 2023
  • 2023-03-30 US US18/192,909 patent/US20230350346A1/en active Pending

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